1. Field of the Invention
The present invention relates to a method of measuring the concentration of cavities (small pores) which occur in a formed product which is formed or processed by superplastic forming.
2. Description of the Related Art
It is conventionally known to form or manufacture products of complicated configurations by superplastic forming with aluminum-based materials or titanium-based materials. However, when these materials are subjected to superplastic forming, cavities are likely to occur due to metallic grain boundary sliding, with the result that the strength of the formed products is decreased.
As a solution, the quality control of the formed products is conventionally carried out by cutting samples of the formed products and measuring the concentration of cavities through a microscopic observation (i.e., by using a microscope).
However, it is impossible in the above-described destructive test to measure the concentration of cavities in all of the formed products. It is therefore desirable to measure the concentration of cavities in a nondestructive method in order to secure the quality of the formed products.